This invention relates to a marine engine protection device and more particularly for an improvement for protecting the engine of the marine propulsion unit in the event the drive unit is tilted up to an excessively high position considering the running speed of the engine.
It is well know to pivotally support a marine outboard drive for movement about a horizontally extending tilt axis so as to adjust the trim position of the propulsion drive and also so as to permit it to be tilted up out of the water when not in use. This is typically done with either outboard motors per se or the outboard drive unit of an inboard-outboard drive. In each application certain problems can arise if the outboard drive is tilted up excessively while the engine speed is maintained at a high value.
With an outboard motor, for example, the water inlet for the cooling of the outboard motor is normally positioned within the lower unit of the outboard motor. Cooling water is drawn from this inlet through a water pump and is circulated through the engine for discharge back into the body of water in which the outboard motor is operating. However, if the outboard motor is tilted up excessively, the water inlet may be at least partially exposed to the atmosphere rather than to the water. This can result in loss of cooling for the engine.
With the outboard drive unit of an inboard-outboard drive, the outboard drive is normally supported for pivotal movement by means of gimbal arms. These gimbal arms normally have extending surfaces that engage the outer portion of the lower unit during its trim operation so as to provide stability. However, if the outboard drive is tilted up so that this engagement no longer exists and the engine is operated at high speeds, the vibrations can cause problems and possible damage to the unit. In addition, serious damage might result during steering movement during such a tilted-up condition.
It is, therefore, a principle object of this invention to provide an arrangement for protecting a marine outboard drive from damage if it is tilted up more than a predetermined amount.
It is a further object of this invention to provide an arrangement for reducing the speed of the driving engine when the marine propulsion outboard drive is tilted up more than a predetermined amount.